In the land of overnight hackathons and round-the-clock production cycles, employees in Silicon Valley spend more waking hours with their co-workers than with their own families, writes April Dembosky in San Francisco.

Bosses refer to their staff as families, with some employees developing close connections to one another that warrant the title “work husband” or “work wife”. This trusted ally and confidant usually sits at a nearby desk, collaborates on projects, and provides a sympathetic ear to sort out office politics.

“Because you spend so much time with your co-workers, you end up knowing what they like eating, what they don’t like eating,” says Cindy Li, a designer at Yahoo’s photo service Flickr. She and her co-worker Brad Peralta both have actual spouses at home. But they text and email each other outside of work all the time.

They are so closely attuned to each other’s schedules and habits that when Li met Peralta’s wife, they discussed his cholesterol levels. “She jokingly called me his ‘work wife’,” Li remembers.

The term dates back several decades, to when secretaries earned the unwelcome title by handling executives’ dry cleaning and buying birthday presents for their kids. Today, with work husband added to the lexicon, the monikers reflect a more equal dynamic, and are used across business sectors. Nearly two-thirds of white-collar workers said they have or have had a work spouse, according to a 2011 survey by Captivate, a digital media company.

But the tech industry breeds a particular closeness. The long hours, and the emotional nature of high-stakes deadlines and fending off competitors, can forge close bonds, says Robin Rosenberg, a clinical psychologist in San Francisco. “They have this shared adrenaline rush together,” she says. “Because so much of the work at start-ups is so intense, it injects a whole other element that a regular job doesn’t have.”

Also, because workers in Silicon Valley tend to change jobs frequently, and hiring relies so much on social networks, such close ties can be valuable for finding opportunities and advancement in the long term.

For Li, the relationships with her co-workers are more than that, especially since her blood relatives all live so far apart.